Microcontrollers and Microprocessors

Wi-Fi modules today are best known in applications in which they are interfaced to Laptops and Mobile Phone processors using the Cardbus, PCI-e or SDIO host interfaces. All these Wi-Fi cards use a device driver and WLAN configuration manager in the host system, usually occupying 100 kB or more of memory. The host itself is a high-end processor that runs a full-functional operating system and performs other general-purpose tasks which are much more memory and compute intensive than the Wi-Fi radio driver. On the other hand, Embedded systems are characterized by their use of one of a variety of micro-controllers ranging from 8-bit versions, with a few kilobytes of instruction memory, low-speed serial interfaces and a few GPIO on the lower-end, to 32-bit ARM9 platforms with audio/video, SDIO, USB and other peripheral interfaces on the higher-end. The wireless connectivity requirements of such systems are therefore varied in terms of the available host interface, limited host memory and required throughputs. Many such systems run a simple RTOS or no OS at all. Even where they include an OS, some may not possess a networking stack. So the choice of how Wi-Fi is to be integrated into an embedded system depends on all of these parameters. And there is a Redpine module for many of these scenarios.